Electrostatic separator



April 10, 1951 J. H. CARPENTER ELECTROSTATIC SEPARATOR Filed Oct. 31,1946 INVENTOR Jame: fia/l Carpenter Patented Apr. 10, 1951 UNITED STATES?ATENT OFFICE ELECTROSTATIC SEPARATOR James Hall Carpenter, Arlington,Fla.

Application October 31, 1946, Serial No. 706,851

3 Claims.

The present invention relates to the electrostatic separation ofmaterials and more particularly to the provision of an improveddischarging electrode for employment with conventional electrostaticseparating machines.

Heretofore, advantage has been taken of the difference in dielectriccapacity of materials to effect a separation of those materials. Ingeneral, the finely divided material to be separated was passed over aso-called separating electrode which was generally cylindrical andcapable of rotation. The separating electrode was connected to one sideof an electrostatic generator, while the other side of the generator wasconnected to a charging electrode adjacent to but spaced from theseparating rotatable electrode or drum. The charging electrode consistedin general of a series of points or a comb from which points a silentdischarge could more readily be effected between the discharging andseparating electrodes.

It is an object of the present invention to provide a more efficientdischarging electrode for electrostatic separating devices. It is alsoan object of the invention to provide an electrostatic separating devicewhich is more efficient in separating materials of different dielectriccapacities than devices provided heretofore.

It is also an object of the invention, therefore, to increase thecapacity of existing electrostatic separating devices by providing moreefficient discharging electrodes therefor.

In the drawing, Fig. 1 is a diagrammatic showing in section of anelectrostatic separating device of the present invention, while Fig. 2is a greatly enlarged showing of the improved discharge electrode.

In accordance with the procedure of the present invention, the materialto be electrostatically separated is placed in the feed hopper l anddischarged therefrom through a suitable feed orifice or slot H on to thesurface of the separating drum or electrode l2. This electrode isgenerally of conducting material such as metal and is rotated at anydesired speed by suitable rotating means not shown. Separating electrodeI2 is connected electrically by any conventional means to one side of anelectrostatic generator 20.

The improved discharging electrode [3 of the present invention is spacedfrom separatingelectrode l2 and is electrically connected to the otherside of the electrostatic generator 20.

The discharging electrode I3 comprises an electrically conductingelement I4 of a diameter very greatly in excess of the diameter of anelectrically conducting wire 15 which is spaced therefrom and which isdirected toward separating electrode I2. The element M as shown in thedrawing consists of a metallic tubular member as, for instance, a metalpipe of about inch in diameter although the diameter may varyconsiderably above or below this figure; the main point being that itshould greatly exceed the diameter of wire [5.

Companion connecting arms [6 and I1 are attached mechanically andelectrically adjacent the ends of tubular member 14 and conducting wire15 is stretched therebetween in conducting relationship. The arms l6 andI1 are of conducting material and have conducting contact with the endsof wire l5 and with tubular member l4. As shown in the drawing thefilamentary wire [5 is held taut between the inwardly bent tips of thearms l6, H in spaced relationship to the surface of the base support l4and substantially parallel to the rotatable electrode l2.

When the improved discharge electrode I3 is directed toward separatingelectrode l2 as shown in Fig. 1, greatly improved separating action isobtained, separations being 50 to more effective on a given materialthan when the conventional wires or combs of prior separating devicesare employed. That is to say, a given degree of separation can beobtained with fewer passes over the rolls than required heretofore. Orcorollary thereto, a given machine when employing the improveddischarging electrode of the present invention can handle a considerablygreater quantity of material in a given time than was possibleheretofore.

It will be understood that the essence of the invention is the provisionof a tube or rod, the diameter of which is greatly in" excess of thediameter of the discharging electrode wire with which it is associated.The actual diameter of these elements have little direct effect upon theseparating process. Thus, at the ratio of 20 to 1, the efiiciency beginsto fall off and one would not get all the benefit of the invention whenoperating with ratio greatly below this. Excellent operating results areobtained with a wire 0.010 inch and a tube of 0.700 inch: in general,the higher the ratio the better.

What is claimed is:

An e ectrostatic separator comprising the c mbination of a rotatableelectrode, and a cooperating soaced electrode, the latter including anelongated electrically conducting support member, electricallyconducting arms extending outwardly from said support member toward saidrotatable electrode, said arms being spaced apart from one another, anda conducting wire mounted upon said arms, said wire being spaced indischarge-supporting relation to said support member, the diameter ofsaid support member being at least about twenty times greater than thediameter of said wire.

2. An electrostatic separator electrode consisting of conductingmaterial and comprising the combination of a rotatable electrode and acooperating stationary electrode, the latter consisting of an elongatedsubstantially cylindrical base which is oriented substantially parallelto said rotatable electrode, arms mounted in said base in spacedrelation and extending outwardly therefrom and a conducting filamentarywire mounted upon the tips of said arms and being held in taut positionsubstantially parallel to the surface of said rotatable electrode, saidbase having a diameter of about 20 to 70 times greater than the diameterof said wire.

3. An electrostatic separator comprising the combination of a rotatableelectrode, and a cooperating electrode consisting of an elongated metalsupport member, electrically conducting arms extending outwardlytherefrom and being spaced apart from one another and a conducting wire,having a diameter of about .01 inch, held in taut relation by said armsin a position toward said rotatable electrode and in substantiallyparallel spaced relation to the surface of said support, said supportbeing about 20 to 70 times greater in diameter than said Wire, said wirebeing positioned normally between said support and said rotatableelectrode.

JAMES HALL CARPENTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 960,470 Wentworth June '7, 19101,386,287 Sutton Aug. 2, 1921 2,249,801 White July 22, 1941

